Productive paddy fields are an important asset in supporting food security. However, due to the increasing competition for land use with sectors outside agriculture, it has triggered the pace of land conversion without control and has the potential to threaten the stability of food supply itself. This study aims to identify the rate of paddy field conversion that occurs in Aceh Besar Regency, Aceh Province, Indonesia. This research was conducted through a spatial approach using the application of Geographic Information Systems (GIS) to identify forms of spatial change based on land use. The method used is a Supervised Classification. The results of the study showed that the highest rate of paddy field conversion occurred in the period 2010-2020 reaching 0.947%/year. This is not comparable to the ability of the substitution efforts made in the previous ten years (2000-2010) which was 0.88 %/year. The form of land conversion that occurred was dominated by the non-agricultural sector, especially residential needs reaching 61.89%. This has the opportunity to reduce rice production by 1,051.38 / year. Therefore, efforts to control the rate of land conversion are absolutely necessary to ensure sustainable food security.

This research tries to identify the chemical state of the soil in the existing citronella planting area in the Gayo Highlands based on altitude, slope, and soil type. The method used in this research is the descriptive method, with data collected through field surveys and laboratory analysis. Soil samples were taken at each observation point by a purposive sampling method, which was determined based on the components forming a homogeneous land unit consisting of six (6) elevation classes, five (5) slope classes, and five (5) soil types. The results of the analysis showed that the highest value of C-organic was found at location Land Unit 6 (LU6) altitude above 1,200 meters above sea level (m asl), which was 7.29%, and the lowest value was found at location LU1 (200-400 m asl), which was 0.81%. While the highest variation of CEC values was found at locations LU6 and LU3 (600-800 m asl) with a value of 56.40 cmol kg−1, the lowest was found at locations LU1. The citronella cultivation area in the Gayo Highlands was studied based on altitude, slope, and soil type at each observation point. It is still suitable to be developed as a citronella cultivation area where the value of soil chemical characteristics found at each research location is in the low to very high criteria and the pH criteria are in the acid to slightly alkaline criteria.